Question

a ball is thrown upward with a velocity 20m/s find the time of flight​

Answer 1

Answer: 4 seconds

Explanation:

Using kinematic equation, v = u + a× t, when ball reaches to top of its trajectory, it's velocity becomes zero. Ball is thrown against gravity of earth, therefore a = - g, u = 20 m/s, we can find time of ascend as

0 =20 - 10 × t

20 = 10 × t

t = 20/10 = 2 sec

Time of ascend is same as time of descend = 2 sec.

Time of flight = time of ascend + time of descend

Therefore time of flight = 4 sec.